Hello i did a fresh install today.
Everything appeared to work at first but some parts of the interface are slow and has missing images.

When i look there are a ton of interface errors. The most obvious is the app center.
Can anyone offer some advice ?

Scared to make the server permanent with these problems.

/univention/js/dojo/dojo.js:6 [Deprecation] Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.
r.getText @ /univention/js/dojo/dojo.js:6
apps-self-service_20151117.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-cups.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-radius.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-samba4.svg Failed to load resource: the server responded with a status of 404 (Not Found)
main.js:1029 Module could not be loaded: umc/modules/reboot
(anonymous) @ main.js:1029
main.js:1029 Module could not be loaded: umc/modules/ipchange
(anonymous) @ main.js:1029
main.js:1029 udm:license-import is not a umc.widgets._ModuleMixin! (2}
(anonymous) @ main.js:1029
main.js:1029 Module could not be loaded: umc/modules/serveroverview
(anonymous) @ main.js:1029
main.js:1029 Module could not be loaded: umc/modules/lib
(anonymous) @ main.js:1029
/univention/js/umc/ Failed to load resource: the server responded with a status of 403 (Forbidden)
/univention/js/dojo/dojo.js:481 e
v @ /univention/js/dojo/dojo.js:481
apps-self-service_20151117.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-radius.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-cups.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-samba4.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-zuludesk_20170623110026.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-z-push-kopano_20170630110344.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-wordpress_20170405170026.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-wildfly_20170427135336.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-webweaver_20150130.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-webuntis_20161128154633.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-wawision_20170111122721.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-univention-demo-data_20151202.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-ucc_20160811170611.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-ucsschool_20170908162422.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-uvmm.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-tine20_20170428121633.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-tecart_20161214101533.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-digitec-suitecrm_20170810160831.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-pkgdb.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-xrdp_20150902.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-squid.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-privacyidea_20170330115620.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-printquota_20161020173421.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-open-xchange-guard_20170620113648.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-open-xchange-text_20170621095529.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-oxseforucs_20170830120807.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-owncloud82_20170427133539.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-owncloud_20170510145711.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-openvpn4ucs_20170615122531.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-opsi_20160927154325.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-openproject_20170704153410.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-onlyoffice-ds_20170728105017.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-noctua_20170412123612.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-nextcloud_20170905134007.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-nagios.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-mobydick_20150527.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-office365_20161123164032.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-maildisclaimer_20170524102325.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-mail-server.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-m23_20170626182521.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-letsencrypt_20170713143310.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-kvm.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-adtakeover.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-audriga-groupware-migration_20131216.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-uvmm-ec2.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-adconnector.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-asterisk4ucs_20170124094112.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-kopano-webmeetings_20170808134523.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-kopano-webapp_20170530164135.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-kopano-core_20170530164016.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-jenkins_20170502110110.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-klms_20150730.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-horde_20161024154423.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-google-apps_20170714095234.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-filewave_20170629161158.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-fetchmail.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-etherpad-lite_20160722133148.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-egroupware_20170703173428.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-dudle_20160201.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-edyou_20141113.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-dhcp-server.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-kde.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-zimbra_20170117144145.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-collabora_20170904150649.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-benno-mailarchiv_20170619120638.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-bareos_20170213162312.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-bacula_20140910.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-iku-av-proxy_20170103114730.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-auralis_20161219103359.svg Failed to load resource: the server responded with a status of 404 (Not Found)
apps-iku-av-mail_20170103114322.svg Failed to load resource: the server responded with a status of 404 (Not Found)

Your error.log shows different timestamps than the entries from your access.log. Therefore the access.log shown doesn’t really help. Can you please post from access.log from when you tried to access the interface? e.g. around 08:42.